• 1.The tripod ring is designed and improved according to Sigma original TS-111. Lens support collar is customized to fit Sigma 100-400mm f/5-6.3 DG DN OS (E-mount) and Sigma 105mm f/1.4 DG HSM Art (EF / FX / FE / L-mount) Not compatible with Sigma 100-400mm f/5-6.3 DG OS HSM Contemporary (EF / F Mount) Lens and other lenses • 2. The net weight of the tripod mount ring is about 170g, the inner diameter is about 82mm, the width is about 18mm, the inner wall has groove and cutout, 3M plastic protective film installed. Locking knob with non-slip design • 3. The tripod collar bottom features a 65mm long Arca Fit quick release plate for direct use with 39mm Arca Swiss Fit tripod ball head, panoramic head and clamp. More practical than lens support collars with no anticut • 4.On the bottom of the lens support collar there is 1/4" and 3/8" screw holes and stainless steel non-slip screws to secure the lens directly to the tripod • 5.The tripod ring is made of aviation aluminum, CNC precision machined, hollow out lightweight design, polished and anodized surface. The appearance and exquisite workmanship is much better than similar products made in molds